Calvin goddard



(No Model.)

G. GODDARD. THERMAL GUT-OUT.

No. 439,398. Patented Oct. 28, 1890.

UNITED STATES PATENT OFFICE.

CALVIN GODDARD, OF NEW YORK, N. Y., ASSIGNOR TO THE EDISON ELEC- TRIO LIGHT COMPANY, OF SAME PLACE.

THERMAL CUT-OUT.

SPECIFICATION forming part of Letters Patent No. 439,398, dated October 28, 1890.

Application filed December 12, 1883- Serial No. 114.285- (No model.)

To all whom it may concern: main conductors e c, enters it, and openings Be it known that I, CALVIN GODDARD, of ff, through which pass the house-wires g g, New York, in the county and State of New covered by insulating-wrappings 71. York, have invented a new and useful Im- The main conductors are clamped upon 5 provement in Safety-Catches for Electric metal plates D and E, and the house-conduct- Light Circuits, of which the following is a ors upon plates F and G all such plates being specification. secured to the insulating-block B. The con- The object of my invention is to provide struction of the clampingdevices is not spean eflicient construction for the safety-catch cifically described herein, as it is claimed in 1o plugs and receptacles therefor used in the myapplication abovereferred to. The plates circuits of systems of electric lighting, to pro- D and E are extended inwardly and form the vide such plugs with devices for readily and bottom plates c' z' of the sockets or receptacles efficiently connecting the circuit-wires to for the safety-catch plugs. Each of such botthem, and to provide means for closing cirtom plates is provided, preferably, with a I 5 cuit around a safety-catch when it is desired conical depression or aperture 70.

to do so in order to prevent sparks when the Secured to, or,if desired, made in one piece safety-catch is removed from or placed in posiwith each of the plates F and G, is the intertion, or to maintain the circuit during the innally-screw-threaded metal ring or band H, terval which may elapse between the destrucwhich bands form the other terminals of the 20 tion of a safety-catch and its replacement by safety-catch receptacles. In these sockets or another, or when it is desired to send out over receptacles are inserted the safety catch the circuit an abnormal current. plugs. These consist each of a block or of I have preferably employed my invention wood or other suitable insulating material, in connection with ajunction-box for making on the outside of which is secured a screw- 2 5 connection between the main conductors and threaded metal ring or band n, forming one the house-wires of a system-such as is set terminal, while the other terminal is a conforth and claimed in my application, Serial No. ical metallic tip a, secured to the end of the 78,747,1iledDeeember8,1882. Saidinvention plug, being of the conical form shown to coris, however, applicable to many other situarespond to the conical depressions 70, whereby 8o 0 tions. an increased area of contact is provided. My invention consists in the novel devices The wooden plug is hollowed out at the top, and combinations of devices employed by me and in the chamber thus formed is placed a in accomplishing the objects above specified, metal clamping plate Z and a clamping-screw as hereinafter set forth and claimed. 0. The clamping-plate Z is electrically con- 3 5 In the accompanying drawings, Figure 1 is nected with the ring-terminal n of the plug a plan view of the interior of an opened j uncby wires 19 p, soldered to the plate and ring. tion-box embodying the features of my in- The lead-wires r 0', which form the safetyvention; Fig. 2, a vertical section of the same catch, are soldered to the ti p-terminals n and through one of the safety-catch receptacles; clamped under the head of the clamping- 0 Fig. 3, a section of a safety-catch plug; Fig. screw 0. One of these plugs is inserted in 4,3.1'1 enlarged perspective view of the termieach of the sockets or receptacles of the nals of such plug, the screw-ringterminalbejunction-box, and a safety-catch is thus ining in section; Fig. 5, a top view of the plug terpolated in each conductor of the house-cirwith its cap removed, and Fig. 6 an elevation cuit. The chambers in the tops of the plugs 5 45 of a guard-plug. are covered by removable metal caps s.

The inclosing-box is made in two parts-a Outside of the sockets the plates D E and metallic frame A, which holds an insulating- F G are extended toward each other and block B, on which the connections are made, flanged to form receptacles it for guard-plugs and a metallic cover 0, which fits over the n, which are inserted when it is desired to 50 frame A. The box is provided with an opencomplete the circuit around the safety-catch ing 0, through which the tube d, containing plugs. Such guard-plugs are inserted before the removal or before the replacement of a safety-catch plug to prevent spark, or may be used to maintain circuit after a safety-catch is destroyed and before the introduction of a new one. This is a matter of great importance in electric-lighting circuits, since it is desirable that in case of emergency the circuit can be kept closed to the lamps without the use of the safety-catch. It occasionally occurs that, the terminals of a safety-catch becoming oxidized, the safety-catch is destroyed while there is yet a safe current flowing for the system. The service of the light must be certain, in order to meet commercial requirements, and hence the guard-plugs are immediately inserted in place. It is often desirable to do this even when the safety-catches are destroyed by an abnormal current, so as to keep up current in the circuit while the load is being decreased to relieve the plant or to burn out a cross on the conductors by concentrating the power of. the plant upon it in the form of current.

What I claim is- 1. The safety-catch plug provided with a conical tip-terminal, in combination with a socket or receptacle therefor having a corresponding depression in its bottom plate, substantially as set forth.

2. A safety-catch plug having a hollow chamber formed in its top, in combination with a clamping plate and screw in said chamber and the safety-catch wires clamped by said plate and screw, substantially as set CALVIN GODDARD. Witnesses:

H. W. SEELY, EDWARD H. PYATT. 

